Method and device for manufacturing a down hole motor radial bearing

Method for manufacturing a down hole motor radial bearing with an anti-abrasion interior surface, said radial bearing having a tubular metal radial bearing body having a fixing surface for fixing it into a down hole motor body and having an anti-abrasion interior layer based on grains of anti-abrasion material buried in a metal matrix,

• the interior surface of the radial bearing being engaged around at least a portion of a drive shaft of the down hole motor, such that the drive shaft is free to rotate relative to the radial bearing, the method comprising the following steps:
• a) providing and holding said tubular radial bearing body having an initial interior surface which is free of grooves,
• b) applying an anti-abrasion material layer directly to the initial interior surface of the tubular radial bearing body by laser-assisted facing, wherein a laser beam is produced by a laser source, the laser beam is directed into a central passage of the radial bearing body as far as a facing area of the initial interior surface, there is simultaneously sprayed onto the facing area a mixture of anti-abrasion material grains and metal powder,
• c) after cooling, machining the anti-abrasion material layer to produce the anti-abrasion interior layer having a final cylindrical interior surface having an inside diameter which is sufficiently large to allow rotation of the drive shaft within the radial bearing, and which is sufficiently small to oppose penetration of abrasive particles contained in a drilling mud,
• wherein step b) is the only applying step before the machining step c).